1. Field
The present invention relates generally to near-field communication and wireless power, and more specifically, to an antenna configured to generate a focused field and a multi-purpose antenna including at least one element for generating a focused field and another element configured for receiving wireless power.
2. Background
Typically, each battery powered device requires its own charger and power source, which is usually an AC power outlet. This becomes unwieldy when many devices need charging.
Approaches are being developed that use over the air power transmission between a transmitter and the device to be charged. These generally fall into two categories. One is based on the coupling of plane wave radiation (also called far-field radiation) between a transmit antenna and receive antenna on the device to be charged which collects the radiated power and rectifies it for charging the battery. Antennas are generally of resonant length in order to improve the coupling efficiency. This approach suffers from the fact that the power coupling falls off quickly with distance between the antennas. So charging over reasonable distances (e.g., >1-2 m) becomes difficult. Additionally, since the system radiates plane waves, unintentional radiation can interfere with other systems if not properly controlled through filtering.
Other approaches are based on inductive coupling between a transmit antenna embedded, for example, in a “charging” mat or surface and a receive antenna plus rectifying circuit embedded in the host device to be charged. This approach has the disadvantage that the spacing between transmit and receive antennas must be very close (e.g. mms). Though this approach does have the capability to simultaneously charge multiple devices in the same area, this area is typically small, hence the user must locate the devices to a specific area.
As will be appreciated by a person having ordinary skill in the art, electronic devices may be configured to transmit and/or receive data via near-field communication (NFC). For example, a device may be configured to communicate with an electronic reader, such as an “Oyster Card” reader. Via NFC, an electronic device may make a payment, gain access through a barrier, or a combination thereof.
With existing antennas and placement thereof within an electronic device, in order to communicate with another device, such as a reader, a user may have to hold the electronic device by its edges or back surface, which is unnatural and may increase the risk of dropping the electronic device. In addition, existing approaches use larger coil antennas that may require that their axis point up and down (i.e., toward a back and front surface of an associated electronic device) as the electronic device is held naturally in a hand of a user.
A need exists for an electronic device having an antenna positioned therein to enable for enhanced user experience. More specifically, a need exists for an electronic device having an antenna suitably position to enable a user to hold the electronic device in a natural position while enabling the electronic device to communicate via NFC with another device. Further, a need exists for an electronic device having an antenna that is adequately positioned for NFC and configured to receive wireless power, transmit wireless power, or both.